Federal prosecutors began arguing in a Brooklyn court on Monday for the death penalty for the prisoner convicted of killing two detectives on Staten Island in 2003.
Ronell Wilson was originally sentenced to death in 2007 for killing NYPD Detectives Rodney Andrews and James Nemorin during a buy-and-bust gun transaction.
An appeals court threw out the sentence in 2010 over a mistake made by prosecutors.
Now, Wilson can only be sentenced to death by a unanimous vote by the jury. Otherwise, he will receive life in prison.
In their opening statement, prosecutors told the jury that Wilson first shot Andrews in head and ignored Nemorin's pleas.
Prosecutors then said Wilson "doesn't give a [expletive] about anyone."
Defense attorneys argued that Wilson had a rough upbringing with a drug-addicted mother and is emotionally disturbed.
Two police officers and a friend of the victims testified on Monday, and Wilson's co-defendant is expected to testify on Tuesday for the prosecution.
The officers' family members were in court Monday, along with Wilson's mother.
These penalty phase proceedings are expected to take about five weeks.
Earlier this year, it was revealed that Wilson had impregnated a federal corrections officer while in prison.